BirdAnalyst
Species · Colorado · BBS 2025 Release · 1966–2024

American Dipper Population Trend in Colorado

All statesGeneralists

American Dipper in Colorado has declined: down 46% on the route-weighted index since 1976.

-46%Since 1976TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
37Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
48YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable American Dipper Trends in ColoradoNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for American Dipper in Colorado. See the full index history below.

American Dipper Population Forecast in Colorado

If the recent trend holds, American Dipper in Colorado is projected to fall about 60% by 2029 — from 0.06 in 2024 to a central estimate of 0.03 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±37.9%, with 100% of held-out values landing inside the 95% band.

-60%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.03Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1595% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±37.9%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, American Dipper in Colorado is projected to fall about 60% by 2029 — from 0.06 in 2024 to a central estimate of 0.03 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±37.9%, with 100% of held-out values landing inside the 95% band.19722029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.030.000.16
20260.030.000.16
20270.030.000.16
20280.030.000.16
20290.030.000.15

American Dipper Survey Routes in Colorado

Routes recording American Dipper in Colorado.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Guanella Pas420242016
Tincup420181992
Buford220172017
Aspen220131979
Lost Lake220121993
Tarryall220091991
Dolores Riv220051991
Lake City219971988
Powderhorn220231994
Fox Creek220241997
Harmony120171979
Trail Ridge Road120062003
Cheesman Lk120221975
Delta119981985
Colona119881976
Parlin120221977
Pagosa Spgs119721972
Rio Grnds Rs120092009
Red Cliff120171989
Castleton120172015
Comanche Pk120142000
Ragged Mtn.119991999
Weston Pass120001994
Marshall Pas120112011
South Fork120111999

American Dipper Population Trend in Other States

alaskacaliforniaidahomontananevadanew-mexicooregonsouth-dakotautahwashingtonwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.